1. Field of the Invention
The present invention relates generally to the transfer of data in a client.backslash.server computer network. More specifically, the present invention relates to the implementing of a multicast protocol in a network, such as a computer network.
2. Prior Art
In order to transmit data over a network an effective transfer scheme for sending and receiving the data is required. Most networks support three basic transfer schemes, a unicast addressing scheme, where the data is sent to one unique device on the data network, a broadcast addressing scheme where data is sent to all devices on the data network and a multicast addressing scheme where data is sent to a group of devices on the data network. Each type of addressing scheme has characteristics that are both desirable and undesirable. The unicast addressing scheme works well in a network system where only one device or client receives data from the data network. If there is a requirement that multiple clients receive data, then the source device or server has to retransmit the data to each additional client. As a number of additional clients increases, the data network quickly becomes over loaded and congested.
The broadcast addressing scheme permits multiple clients to receive the data without requiring the server to transmit multiple sets of data. The broadcast data, however, is also transmitted to clients that are not interested in the data. These clients have to receive the data and reject it. Thus the broadcast of data onto data network affects other clients on the data network.
The multicast addressing scheme enables the transmission of data to be received by a select group of clients on the data network system. Clients typically communicate with the server and request to be added to a specific group of clients in order to receive data that is transferred to that specific group. Thus, a multicast addressing scheme is suitable for the selective transmission of data.
The traditional multicast scheme operates in a manner in which a specific client requests the server to place that client in a specific group so that the client can receive that groups specific data or multicast packets. Typically, the server has no control over which clients are placed within which group.
There remains a need for a method and system which allows for the server to have control over which clients are to be placed within which multicast group.
Therefore, it is desirable to design a client.backslash.server network capable of allowing the server to assign clients to specific multicast groups in order to receive specific multicast packets.